From DE 102 07 017 A1, an apparatus is known for measuring the lift height of a load support device on a lift frame. The lift mast itself has a stationary frame fixed to the vehicle and at least one extendable lift frame. The height measuring apparatus has a measuring sensor and at least one position generator that is movable in height. The position generator is designed as an elongated generator disposed in the region of the lift mast that interacts in a contact-free manner with a measuring sensor fastened to the stationary frame.
The contact-free measurement has the advantage that no wear occurs at the measuring apparatus. However, measuring inaccuracies can occur that arise due to a relative movement between the measuring sensor and the position generator.